A novel method to control atomic defects in graphene sheets, by selective surface reactions

Behaviors of atomic defects in graphene sheets in air at high temperature are studied. Results indicate that the number of defects in graphene sheets decreases after high temperature treatment in air. Mechanism for the behaviors are studied by molecular simulations and interpreted as follows. Charge distributions of atoms in graphene sheets are relatively uniform due to large conjugated π bond, but atomic defects in the graphene sheets change the uniform charge distributions. The change of charge distributions makes these defect-regions have higher chemical activities, thus these defect-regions are easy to be eroded selectively by O2 in air, which makes the number of them decrease. Thus, high temperature treatment in air can be used as a novel method to control atomic defects in graphene sheets. However, in order to obtain the graphene sheets after reactions, two problems should be dealt with: one is sufficient contact between air and graphene sheets during reaction; the other is transfer and enrichment of graphene sheets after reaction. Our method dealt with the two problems.